Arize Phoenix is one of the most popular open-source LLM observability platforms in 2026. If you are evaluating it alongside CortexOps, this article compares them directly on the things that matter for production agent workloads.
Short version:
Arize Phoenix is the right choice if you are doing notebook-based experimentation, RAG evaluation, or need embeddings analysis. It is well-established with 9,000+ GitHub stars and strong OTel support.
CortexOps is the right choice if you need a first-class CI/CD deployment gate, multi-framework agent tracing beyond LangGraph, or a flat-rate pricing model that doesn't get expensive at agent-scale span volumes.
What They Are
